In known tamperproof closing means of this type, the container neck exhibits, at its base, a plurality of circumferentially oriented radial catches. A tamperproof band exhibits a plurality of inside radial lugs with a profile complementary to that of the neck lugs, i.e., circumferentially oriented in the opposite direction, the orientations and dimensions of the catches and lugs being configured to permit passage of the latter over the former in the direction of screwing, because of the elastic deformation of the constitutive material, and to oppose this passage in the opposite direction.
A maneuver of the cap in the unscrewing direction, because of the holding of the band by the catches of the neck, causes breaking of the material bridges which connect it to the skirt of the cap.
In these known tamperproof closing means, nothing prevents the band from descending along the neck in case of prohibited or unauthorized opening of the container, which would make possible an immediate detection by a simple glance at this opening. On the other hand, nothing prevents the band from falling into a glass when, after opening the container, the container is tilted in the direction of the glass to pour all or part of the contents of the container into the glass.
These closing means further have the drawback of not effectively protecting the tamperproof band from the risks of tearing before opening of the container, especially during manueuvering of the containers by a packer.